Some three-dimensional (3D) printing techniques print an object by successively forming a series of material layers in accordance with a 3D model of the object to be printed. Some companies, such as SHAPEWAYS, provide on-demand 3D printing services where customers may upload custom 3D models, select materials, and order printed objects to be built from selected materials. These on-demand printing services allow customers to convert a custom 3D model into any number of printed objects without the expense of purchasing and operating a 3D printer.